Instructions for Visiting Astronomers

One month before your scheduled run

By this time, you should have received the announcement of your time allocation, available at the visas pages using your personal ID and password (if you have not received this webletter or the ID, please contact; that message contains important information about your run and the related logistics. In particular, you have to fill the travel information if you have not already done so (if you have already organized your trip with va-travel, you are set, no need to re-contact them because of this mail).You are invited to consult the documentation available on Paranal Science Operations Web Page, in particular the section for Visiting Astronomers.

Less than 30 days to your arrival on Paranal

it will be beneficial to start with the observation preparations:

  • read the User Manual,
  • learn how to use the Preparation Software,
  • know how to use P2PP,
  • be able use the ETC to estimate the exposure time (DIT)
  • have a defined observing strategy:
    • which observation templates do you plan to use, in which order, and which instrumental set-up will give you the best outcome?
    • Do you need special calibrators? We have many OBs for normal standard stars and day calibrations ready for use, but if you have special requirements, you should prepare these too.
    • Prepare your list of targets: remember that you can only observe those targets listed in your Phase 1 proposal. If you wish to change targets, or if you need additional targets, you will have to request them. Remember that we often have strong wind from the North (meaning that you will have to observe south of -25deg Dec), and backup targets might also be needed.Check out the Visitor Mode Phase 2 Preparation Program (P2PP) recommendations . ADDITIONAL AND BACKUP TARGETS, AS WELL AS SET-UP CHANGES must be requested and approved in advance using a specific procedure.

When arriving on Paranal

You will normally have 2 nights in order to finalize your observation strategy and your observation blocks together with your support astronomer.

Should you have any technical question, send an email to naco at

For scheduling questions, please address your email to visas at

The Observatory has prepared OBs for most of the setup necessary for photometric standards calibrations. They can be used at anytime for a visitor run and if needed can be modified online (at the console) to use narrow band (NB) and/or intermediate band (IB) filters.

For Telluric standards, PSO has developed a special tool which allows to querya list of Hipparcos stars for which magnitude (visible & infrared) and spectral typeare known. This tool will be used by the night support astronomer to produce an OB with the same setting as your science OB. It is thus not compulsory to prepare spectrophotometric OBs before the beginning of the night; except if a special standard must be used.

The detector integration time (DIT) can be adapted at the beginning of each observation,to adjust the S/N and the saturation levels. The night support astronomer will help youto determine the best value, then it will be your responsibility to enter the correct valuein the corresponding OB using P2PP (in the control room).
Extreme saturation of the detector (more than a factor 5) is subject to request and must have been accepted by the head of PSO &/or the NaCo instrument'scientist before the observation.

Calibrations of the data taken over night are done automatically the next morning. The completeness and quality of these calibrations arechecked by your daytime support. Only special request OBsneed to be prepared by yourself.
Weather permiting PSO will take twilight sky flats according to the Calibration Plan. Since it is a slow process to get a full set of possible filters/cameras combinations, it is important for us to know upon your arrival the list of settings you will be using.